Very few celebrated instrumentalists have been able to make the leap into conducting without lowering their standards. To be sure, some listeners consider Vladimir Ashkenazy as fine a conductor as he is a pianist, and there are those who would argue that Mstislav Rostropovich leads Russian orchestral music with the exalted intensity that he brings to the best of his performances on the cello. After that, the list grows mighty thin -- this, despite the fact that famous flutists, trumpeters, violinists, violists, cellists and any number of pianists have undergone conversion, declared themselves conductors and set up shop.

Peter Oundjian, who led the National Symphony Orchestra last night at the Kennedy Center Concert Hall in a program of music by Rimsky-Korsakov, Tchaikovsky and Beethoven, is a special case. Oundjian was the first violinist in the Tokyo String Quartet for 14 years until he developed an unusually acute repetitive stress injury that forced him to retire.

But abandonment of the violin did not necessitate the abandonment of music, and by force of will Oundjian made himself a conductor. He became the artistic director of the Caramoor Festival in Upstate New York, the principal guest conductor of the Colorado Symphony and, as of 2004, the music director of the Toronto Symphony Orchestra.

I think the fact that Oundjian was always a member of an ensemble rather than a solo virtuoso has helped his transition to the podium. His manner of musicmaking is collegial rather than authoritarian; although there is rarely any doubt as to who is shaping a given performance, Oundjian seems less a dictator than first among equals, urging his colleagues on.

Rimsky-Korsakov's "Capriccio Espagnol" might be likened to one of those exhaustive physicals in which every part of the body is examined in minute detail. Most of the first-desk players, from the concertmaster to the harpist, perform solos, and -- as in most physicals -- there was better news from some sections last night than from others. Yet there was vigor throughout, and color, and elan. Assertive passages were the aural equivalent of blinding in their fierce intensity, while Oundjian proved himself adept at shaping slow, sparse music without leaving a listener with the impression that nothing very important was going on.

Tchaikovsky's "Variations on a Rococo Theme" was even better. The cellist was 23-year-old Alisa Weilerstein, who would seem to be a genuine prodigy. She played the opening melody, one of Tchaikovsky's loveliest, with a rare mixture of elegance and wit, forged through the faster variations with dancing energy, sang out throbbing slow melodies as though they were Italian opera and even made the virtuosic runs and pyrotechnics toward the end of the piece musically, as well as technically, interesting.

Beethoven's Symphony No. 3 concluded the program. Citing the composer's ever-controversial metronome indications -- ignored or dismissed by conductors of the "Eroica" for most of the past two centuries -- Oundjian favored brisk, assertive tempos. But what especially impressed me was how softly he had the orchestra play most of the time, which made the great fortes in the opening movement and at the crisis in the funeral march all the more violent and affecting. The Scherzo was as playful as one could have wished for -- even the horns managed to stay pretty much in tune during their brutally exposed solo passages -- and the finale was shot through with a near-Rossinian sense of mischief.

The program will be repeated tonight at 8. Although the NSO's official "Opening Night" is still a couple of weeks off, the season has already begun -- triumphantly.